Engine Strange water dripping sound immediately after turning engine off

R82148V · Sep 21, 2023

Hello all,

I have a strange one for you. I could be again over thinking it or perhaps there's and issue brewing.
I've started to notice a strange water draining then dripping type sounds once the engine is turned off.
It doesnt ever over-heat with gauge right in the middle. I checked the coolant level and its to the top. At running temp, coolant does expand in the expansion tank.
Oil looks good. Oil pressure is mid to a little upper on the stock gauge.
The sound is more concentrated on the passenger side I feel.
Would this just be oil draining back into the pan or something I should be worried about?

I'm not too sure if this always happened or just started. In any case, I hear it now haha but only with the hood up as I turn it off.

what does everyone think or what should I check?

Noobz347 · Sep 21, 2023

It's your Air Conditioner Evaporator Drain

Mustang5L5 · Sep 21, 2023

Check the condensation drain port on the pass side lower firewall.

You are either leaking water from the ac on the exhaust, or leaking coolant from a leaking core.

Both my mustangs do the same when I run the ac. Drip and maybe a slight sizzle.

R82148V · Sep 21, 2023

I don’t run the AC. It’s installed but it doesn’t work since it needs refrigerant. can it still be the AC evap drain? it does sound like water draining and then dripping once the engine is off.

General karthief · Sep 21, 2023

You may be hearing the heater core water pressure equalizing.

Noobz347 · Sep 21, 2023

There is a restrictor in one of the lines for the heater core from the factory. I should be on the inlet side if it still exists.

R82148V said:
I don’t run the AC. It’s installed but it doesn’t work since it needs refrigerant. can it still be the AC evap drain? it does sound like water draining and then dripping once the engine is off.

Unlikely... You could double-check and see if the AC runs.

R82148V · Sep 22, 2023

General karthief said:
You may be hearing the heater core water pressure equalizing.

oh man what does that mean? please tell me that's ok.

R82148V · Sep 22, 2023

Noobz347 said:
There is a restrictor in one of the lines for the heater core from the factory. I should be on the inlet side if it still exists.

Unlikely... You could double-check and see if the AC runs.

This convertible was / is a restoration project and I did change out the two small hoses going to the heater core. I dont remember ever seeing a restrictor in line. Is it needed?

Noobz347 · Sep 22, 2023

R82148V said:
This convertible was / is a restoration project and I did change out the two small hoses going to the heater core. I dont remember ever seeing a restrictor in line. Is it needed?

"Needed" is a harsh word.

Lots of folks unknowingly discard them. How many of those have had heater core issues as a result is hard to say.

R82148V · Sep 22, 2023

Noobz347 said:
"Needed" is a harsh word.

Lots of folks unknowingly discard them. How many of those have had heater core issues as a result is hard to say.

i'll be sure to put a restrictor in. I'm just hoping that water sound is the heater core water pressure equalizing and not a blown core. Sounds sort of like a shower turning off and few drips afterwards. I don't see any wetness inside the car or out that drain on the firewall.
I'll check the condensation drain port for blockage though..

Mustang5L5 · Sep 22, 2023

Are you loosing coolant at all?

Noobz347 · Sep 22, 2023

Here is a link for a replacement if you're searching:

Mustang Heater Core Flow Restrictor (79-04) E7VY-18358

Reduce the coolant pressure flowing into your heater core with this heater core flow restrictor for 1979-2004 Mustang!

lmr.com

R82148V · Sep 22, 2023

Mustang5L5 said:
Are you loosing coolant at all?

No coolant loss at all. Took the cap off which released a little pressure but it was right at the top. The overflow tank is right on the cold line too.

R82148V · Sep 22, 2023

I just stuck a 6 inch long cleaning q-tip in the condensation drain port to see if it would come out wet and it was bone dry.
I also checked inside under the dash and that was dry too.
I guess next, test would be to run it and run the heat or defrost and look for fog or that coolant smell?

Mustang5L5 · Sep 22, 2023

It’s likely air trapped in the heater core.

R82148V · Sep 22, 2023

Mustang5L5 said:
It’s likely air trapped in the heater core.

I have a coolant burping funnel kit that i’ll try to see if there is air in the system and let you know what i find. Thank you for everyone’s time and have a great weekend!! I’ll report back.

General karthief · Sep 23, 2023

I'm wondering if he is hearing that 'tic tic tic' sound that contracting metal make when it starts cooling off?

Blown88GT · Sep 23, 2023

Noobz347 said:
There is a restrictor in one of the lines for the heater core from the factory. I should be on the inlet side if it still exists.

Unlikely... You could double-check and see if the AC runs.

No restrictor from the factory on my '88. Heater core gave out 2 years ago, so bypassed it with a hose. No heat needed in S. FL.

Noobz347 · Sep 23, 2023

Blown88GT said:
No restrictor from the factory on my '88. Heater core gave out 2 years ago, so bypassed it with a hose. No heat needed in S. FL.

Are you the original owner of the car?

...and note that the restrictor is not part of the hose or rather did not come as part of the hose.

...and also note that the OEM restrictor was metal and not plastic and was, for observation purposes, [pressed] into the hose meaning that the fit was very tight. It would have felt just like a hard spot in the OEM inlet hose about a 1/2 inch to 3/4 inch long.

This image shows the original location:

It's also a better representation of the size and shape of the OEM piece.

Mustang5L5 · Sep 23, 2023

I had a restrictor in the hose on my ‘88. I’d have to think it was original as I’ve owned the car since 45k miles or so. I cannot confirm however.

When I redid my engine I tracked down some nos hoses and they did have a restrictor. I don’t recall the p/n on the hose.

Engine Strange water dripping sound immediately after turning engine off

Active Member

Stangnet Facilities Maint Tech... Er... Janitor

That is…until I whipped out my Bissell

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wonder how much it would cost to ship you a pair

Stangnet Facilities Maint Tech... Er... Janitor

Active Member

Active Member

Stangnet Facilities Maint Tech... Er... Janitor

Active Member

That is…until I whipped out my Bissell

Stangnet Facilities Maint Tech... Er... Janitor

Active Member

Active Member

That is…until I whipped out my Bissell

Active Member

wonder how much it would cost to ship you a pair

Stangnet Facilities Maint Tech... Er... Janitor

That is…until I whipped out my Bissell

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